The present invention relates to a fuel injection pump for an internal combustion engine which may be, but is not limited to, the distribution type.
Fuel injection systems are popular in the field of internal combustion engines due to their many advantages, especially where adapted to combustion ignition or Diesel engines. Typical of such systems is the distribution system in which a plunger is simultaneously rotated and reciprocated to pump fuel to injection nozzles of a number of engine cylinders.
In a known distribution type fuel injection pump, a fuel control sleeve is positioned by flyweights to control the amount of fuel injection in accordance with engine speed. The flyweights urge a governor rod toward a tension lever as the engine speed increases.
A problem has existed in this type of pump in that a stroke of the governor rod available with the flyweights is limited due to the inherent arrangement and, thus, zero fuel injection is unachievable at the no-load maximum engine speed condition should a substantial stroke of the governor rod be employed for increasing the amount of fuel injection for a start of engine operation.
Meanwhile, a fuel injection advance angle control member of the pump is generally designed to move to increase a fuel injection advance angle as the engine speed increases. This gives rise to another problem that the angle cannot be increased for a start of engine operation.